To improve professional practice, educators need sound principles about how learning works to guide their pedagogical decisions, actions, policies, and practices. Such principles as teaching for fluent and flexible transfer, incorporating big ideas that connect isolated facts, and providing user-friendly feedback make learning meaningful for students and teachers alike. Schools need a standard that enables them to decide, case by case, whether a teaching practice or professional development activity is truly professional. Only by referring to valid standards for learning--which faculty members have developed and agreed to uphold--can true learning take place. School leaders need to continually demand new learning and help staff clarify which practices advance, and which unwittingly impede, learning in their schools.